Adaptive Control of Variable Geometry Inlet–Configured Air-Breathing Hypersonic Vehicles

This paper studies the longitudinal fault-tolerant control problem for a class of variable geometry inlet-configured air-breathing hypersonic vehicles, whose inlet length varies dynamically to ensure an efficient scramjet thrust. After lumping the effects of uncertain parameters, external disturbances, flexible dynamics, actuator faults, and variable inlet into the linearly parameterized form, a parameterized control-oriented model (PCOM) is derived for design purpose. To handle the time-varying uncertain parameter vectors involved in the PCOM, a novel bound estimation method is developed, while greatly reducing the required parameter update laws. In the adaptive back-stepping design for altitude subsystem, the command filter technique is implemented to circumvent the analytical derivative calculations of virtual controls that are unmanageable by a standard back-stepping procedure because of the time-varying uncertain factors in the PCOM. The corresponding tracking errors are regulated into adjustable residual sets. A simulation study is implemented to verify the developed controller.